Abstract
To understand the fundamental and overall characteristics of thermal environment in coastal areas, a comparative analysis based on a set of long-term data of water temperature variation has been performed for the Tokyo Bay (semi-closed bay), the Kashima coast (open coast) and the Kasumigaura (lake), which are located under similar weather conditions. The results show that, all through the year, the water temperature variation in the Kasumigaura is governed by the heat flux through the water surface such as solar radiation, whereas that in the Kashima coast is dominated also by the horizontal convection. In Tokyo Bay, in summer, the water temperature variation in the surface mixing layer in the time scale more than one week is mostly governed by the vertical heat flux through the water surface. Since the heat is accumulated in the surface mixing layer and its average depth is comparable to that of the Kasumigaura, the subsurface water temperature in the Tokyo Bay exhibits nearly the same variation with that in the Kasumigaura. In winter, on the other hand, the horizontal heat flux through the baymouth from the Pacific Ocean influences the water temperature even at the head of Tokyo Bay.
